Equifax questioned 397 of the 430 councils that release Roll data for marketing purposes. The survey revealed that 62 per cent of them planned to pre-tick next year.
Pre-ticking of Roll forms contravenes new regulations forbidding such activity and the Direct Marketing Association has been lobbying individual councils to ensure its enforcement.
The latest news will come as a blow to high-volume mailers who use the Roll as a base file.
A 2004 survey by Skipton Information Group plots the UK opt-out average currently at 29.87 per cent, up from the 26 per cent figure in 2004. This figure now stands at nearly 10 per cent higher than the 20 per cent figure for 2003 - the first year that Electoral Roll opt-out was available.
This means 3.3 million UK consumers have now opted out since 2003.